INTRODUCTION

Lighting at fitness area has always been an important part of safety to the society. However, its importance has been highlighted due to incidences that had happen before, such as robbery, rape and other dangerous activities. Study have been done by investigator at Los Angeles proven that the safety issue had led to health problem in the society and residential area. Residents are found to be more likely to stay indoor if they declared surrounding is dangerous and the risk for them to get illness is higher [1]. Solar lighting system at fitness area in Recreation Park does not only will help to reduces crime at that area, but help to improve the health condition of the residents at that area.

Besides of that, due to the working culture and job limitation in Malaysia, adults are only able to enjoy their leisure time at night. This had brought up the issue of insufficient of light system at fitness area in the Recreation Park. From the survey that had been done by our group, users of the Recreation Park are complaining about the lacking of light or low brightness at the Recreation Park which make them afraid to go to the park during night. They also worried about the appearance of suspected person at the park area during night when there is not light at the park. Therefore, users at the Recreation Park are strong suggested to install lighting system at the fitness area in the Recreation Park.

Therefore, in order to solve the problem mentioned, for this project, solar light system at fitness area is purposed. In this project, solar energy which is the cleanest renewable energy is purposed [2]. Solar energy is energy generated from radiation of the sun capable of producing heat, causing chemical reactions, or generating electricity. Solar radiation is converted directly into electricity by solar cells (photovoltaic cells). When light strikes the junction between a metal and a semiconductor or the junction between two different semiconductors small electric voltage will generated. Only about two watts the power generated by a single photovoltaic. It also can generate hundred or even thousands of kilowatts of electric power by connecting a large number of individuals cells together in a solar electric plant. The energy efficiency of most present-day photovoltaic cells is only about 15 to 20 percent, and since the intensity of solar radiation is low to begin with, huge and costly assemblies of such cells are required to produce even moderate amounts of power. Malaysia is exposed to sunlight for 4 to 8 hours every day which make the solar energy is the most suitable renewable energy to implemented in Malaysia and at in Johor Bahru area [3].

In this project we are also implement an eco-friendly light source which is water and bleach solution based on the concept of “A Litre of Light”. “A Litre of Light” is a method used to design a low cost light which suitable to implement at rural area with no enough energy supply or poor area [4]. This is a design inspired by Alfredo Moser from Brazil and applied socially at Philippines. The design method is simple by preparing a solution mixed with water and bleach and filled in a bottle.  By using the theory of refraction of light, the bottle of solution is able to generate a very bright light at a dark area.

In this project, a system which combining the power supply system from solar energy, control system using programmable embedded system, and monitoring system using GSM module is introduced. The applicable of the system in real environment is discussed as well.

IMPLEMENTATION

The materials that needed in this project were purchased from hardware store and online store which in affordable price. The assembly for the materials was started with the first part on piezoelectric-sensor mat.

After that, the stand for the solar panel was constructed. The stand was made up from slotted angle steel which connected by bolt and nuts. The stand was designed in two layers in order to increase the height for the solar panel for sunlight absorption. The height for the stand was set in 50 cm. Two slotted angle bars with the length of 3 meters each is bought. The bars is cut into 3 different lengths; 35cm (4), 55cm (4) and 50cm (4) in order to use to build the stand as mentioned above. We use Electronic Lab at P10 to do the cutting using hand grinder machine.

Following by solar panel stand, the PVC poles for the light poles were constructed. The two PVC with diameter of 15 cm were cut and polished at their both end. After that, one end of these two PVC was connected to the wooden base with bolt and nuts. While for the other end was used to hold the container, which contained the bleach solution. The containers were made of plastic and appeared in crystal shape. Moreover, LED was used in the light poles instead of traditional incandescent light bulb as the power consumption for LED is lower and able to last longer. The decoration of PVC poles was used the carbon tinted paper which made them tidier in appearance and rougher to the environment condition changes.  Holes is drilled at the bottom of the PVC poles in order to put the circuit into the PVC poles for waterproof purpose.  The light pole is shown below.

2 x 5m LEDs strips shown below is bought from online store to use as the normal lighting system during night in our system.

A micro-controller was used to control the system automatically. Arduino UNO served as the micro-controller and its function was to control over the time delay operation of piezoelectric-sensor, light sensor, Global System for Mobile (GSM) module and switch.

For this system, two types of sensor and one module were used. The first sensor was the piezoelectric-sensor which looks like a disc. There are two layers of materials on the disc and when the disc is vibrated, it will generate a voltage. The amount of voltage generated is depends on the degree of vibration done on the sensor. The stronger the vibration applied to the sensors, the higher the voltage generated from the piezo disc. In our testing and experiments, the voltage ranges from 0.5 V to 2.0V. The voltage signal is connected to the analog read pin of Arduino Uno. When the users stepped on the piezo mat, the piezo disc is vibrated and there will be a voltage signal input into Arduino, then a 5V digital output will be directed out from digital pins of Arduino to trigger the relay and turn on the main lighting (LED lighting inside the PVC pole) in the park. Besides, when there are no users stepping on the mat, the light will not immediately turn off, it will be delayed by 15 minutes using timer in order for the users to leave the park safely. However, if the users are still using the park, he can always step on lots of piezo mat being scattered on the park since the circuit of piezo mat is connected in series and whenever one mat is stepped on, the whole system will be turned on.  

 The second sensor used was light sensor. It was detected the changes in light intensity at the early night and always switched on the lighting system automatically started from 7pm to 7am of next day. Moreover, a GSM module was used for the alert system of battery of solar panel. It is the real-time monitoring system with IOT for battery status either in low battery status or affect by some unexpected condition. Alert message will be send out and the mobile application will show the status of the battery spontaneously. Figures below shown the monitoring system applied in our project. 

OPERATION

The electronic components and the hardware parts had been connected and placed in Dataran FKE for the system testing. Since the testing area was at the stair side, the LED strips were attached to the both side of handles. While the piezoelectric mats were putted on the both end of the stair and the PVC poles were located on the lower end of the stair. After that, wiring process through whole system was done and the solar panel was connected to the battery and charge controller. For this project, LED strips were able to show in various color effect in red, green, blue and white colors. The brightness of the LED strips was brightened up the stair area.

While for the functionality of piezoelectric mats, they were tested by the stepping of person on the mats surface. The solar bottle on the PVC poles were lighted up after the stepped-on mats. However, the operation time of the solar bulb was set for 15 minutes in the means of power consumption saving and it will be waiting for next step on the mats to be on after 15 minutes. The circuit for Arduino UNO was checked and ensure every soldered part were in good condition.

The system is tested with full functionality at night as shown in Figure 2.19.  During the night, the system is activated by the light sensor module.  The LEDs strips is light up as the light for the path at the stairs. When someone come into the area and stepped on the piezo matt, the light poles is lighted up.

RESULTS & DISCUSSION

The implementation and operation of our system is successfully imitate the real condition of applying our group’s concept the recreation park.  The operation of our system is following the condition required which the light source is light up during night time and the light poles is light up for 15 minutes to provide extra brightness to the fitness area in the Recreation Park. Our system does not only provided sufficient brightness to the area, but also provided a solution of lighting system with low power consumption and eco-friendly power source.

Solar energy is a renewable energy and sustainable energy which have been given very high attention by scientists and academicians.  In this project, solar energy is used as the main power source of the system to supply to all the loads installed to the system.  However, as mentioned before, the power generated by the solar panel or solar cell is fluctuated and unstable.  The power generated is greatly depends on the condition on the day and the amount of sunlight penetrated to the solar panel.  Therefore, in order to provide sufficient energy to the system, it is important to understand the power can be generated by the solar panel and prepare sufficient amount of the solar panel to support the system.

Some experiment have been carried out to find out the energy can be generated by the solar panel and the energy will be consumed by the loads.  The materials used in the experiment is the materials used in the implementation and operation of our project, which imitate the real system that will be apply at the recreation park.  The first experiment is carried out by finding the energy can be generated by the 20W, 12V solar panel.  The experiment is carried at P04 FKE from10:00am to 2:30pm.

The second experiment is carried out to determine the power consumption of the load using in our project, which including the 2 x 5m LEDs strips and two light poles.

Third experiment is investigating on the power consumption of the system by 2 x  5m LEDs strips.

From the data, the power can be stored when using 20W,12V solar panel in one hour is 0.72W. Assumed the day is good enough for charging the battery for 7 hours, the total power stored by one solar panel and battery combination is 5.04W.

The power consumption of our system is shown below:

Assumed all load is power up for 3 hours in the night time (7pm to 10pm).

Power consumption = 3.24Wx3 = 9.72W

Assumed from 10pm to 7am, only 2 5m LED strips is power up.

Power consumption = 2.05Wx9 = 18.45W

Total power consumption in one day = 9.72W+18.45W = 28.17W

Let 30 W to be the worst case scenario of the power consumption in one day.

The power can be stored in one day is 5W for one solar panel. Therefore, in order to supply the whole system, 10 set of the 20W solar panel with battery have to prepare.

In order to improve the efficiency of the solar panel in generating solar energy, researches had introduce several ways. One of the example of technology applied is Concentrated Photovoltaic technology (CPV) introduced by Rizwan Arshad [8]. This technology is using mirror or lens to concentrate the sunlight onto the solar panel so that the solar panel is able to generate more power with same amount of solar panel used.

Besides of the power consumption, in order to apply our system at the fitness area in the Recreation Park, the circuit have to be sealed up for waterproof purpose.  The circuit should be placed in the PVC pipe. This will be able to protect the circuit from damage due to water or vandalisms. 

The piezo matt have to distribute all around the fitness area. This is to ensure that the light poles is always light up when there is someone in the fitness area of even in the Recreation Park.  If the distribution of piezo matt is no large enough, the park will become dark when 15 minutes is over.

CONCLUSION

This project is a capstone project using CDIO (Conceive, Design, Implement, and Operate) framework.  By following this framework, engineers are able to produce the product on time based on the timeline set. In constructing a product, besides of clear management and good planning, team working among members is also very important.

In our project, the prototype is operate as expected.  The lighting system is light up when needed and shut up during day time.  This will save a lot of energy.  The prototype is ready to be implemented at the fitness area at the Recreation Park. 

In short, by participating in this project, we have the chance to learn and apply knowledge practically and this is very important to an engineer.  The programming skills, circuit design skills, mechanical skills, and control system design skills applied in this capstone project had prepare the students as an Mechatronic Engineer.